1. Technical Field of the Invention
Implementations consistent with the principles of the invention generally relate to the field of battery technology, more specifically to three-dimensional energy storage systems and devices, such as batteries and capacitors, and methods of manufacturing thereof.
2. Background
Existing energy storage devices, such as batteries, typically lack good thermal conductivity to facilitate removal of heat generated within the cell from the cell. In traditional battery packs as much as 50% of the pack volume and weight is dedicated to thermally conducting structures to remove heat from the cells.
For example, in a conventional jelly roll type energy storage device there is no direct, high conductivity path for heat to escape from the center of the cell. FIG. 1 shows a cross-section of a conventional jelly roll 100, constructed by rolling several alternating layers of anode electrode material 110 and cathode electrode material 120 into a cylindrical shape with separators 130 between each successive cathode layer and anode layer. A typical example of a jelly roll is consumer Nickel Cadmium batteries, sold in standard sizes AAA-D. As shown in FIG. 1, the jelly roll cell has good circumferential thermal conductivity 140 within each electrode layer, but this does not help remove heat from the cell. The heat generated near the center of the cell has to move radially 150 across each electrode and separator to reach the outside of the cell. The thermal conductivity of each electrode is very poor (approximately 1-3 W/m-K) compared to silicon, and the thermal conductivity of separator material is even worse (approximately 0.3 W/m-K). The jelly roll cell thus has poor radial thermal conductivity.
Another common design is the prismatic cell, commonly used for mobile phone batteries, which employs a thinner, typically substantially rectangular prism shaped, design. A conventional prismatic cell is constructed of alternating layers of anode electrical material and cathode electrical material wrapped into a substantially rectangular prism shape with separators between each successive cathode layer and anode layer. The typical prismatic cell has fewer electrode pairs when compared to a comparable capacity jelly roll cell. However, there is still no direct, high conductivity path for heat to escape from the center of the prismatic cell. As with the jelly roll cell, any heat generated in the inner electrode layers of the prismatic cell has to travel through multiple layers of electrodes and separators to escape the cell.
The following reference may further help to illustrate the state of the art, and is therefore incorporated by reference as non-essential subject matter herein: Long et. al., “Three-Dimensional Battery Architectures,” Chemical Reviews, (2004), 104, 4463-4492 (“Long”). Long discloses various 3-dimensional battery cell architectures, but does not describe how to incorporate such cell architectures into useful modules or battery packs as disclosed and claimed in the present application. Long does not teach or suggest how to solve the problem of thermal conductance while containing the electrolyte, as solved by the present invention.
It would be desirable to incorporate battery cells into compact battery modules and battery packs without requiring additional structure to remove heat generated within the cells.
It would be desirable to make battery packs with increased pack energy density for a given cell energy density, while addressing the above issues or other limitations in the art.
It would be desirable to make battery packs with improved thermal performance with reduced weight and volume, while addressing the above issues or other limitations in the art.